I haven't seen either but miss kdd has so many good reviews for being absolutely filthy so would see her
On a separate note is it just me or have most of her fanclub seemingly stopped posting on this site?
As the founding member of her fanclub, I'm still here

albeit not punting with her or anyone.
OP, you can't really go wrong with either. In my opinion MissKDD is filthier, but it's hard to quantify why, Lia does all the same services. It's just the way it's delivered. Other punters will prefer Lia's style. They both look quite different so there's that to consider depending on your tastes. They also make for a top notch duo

Although there are no pictures, MissKDD is accurately described in many reviews here, however, if pictures are a MUST for you then it's certainly a risk. I think one reviewer here mentioned that he
was disappointed with her look,
but thoroughly enjoyed the service and would book again..so you need to weigh it up. I think she's very pretty so YMMV as with all things punting. Lia is excellent, no doubt about it, and I've never been disappointed with her service.
As for Rio Lee, I haven't seen her since a duo with MissKDD and she was very good back then. Definitely the most squirting I've ever seen in a punt between the two of them

Jerboa recently posted a positive review on Rio Lee with a couple of caveats around the filth level though..